This invention relates to a gear arrangement for driving the spool core of a take-up spool for a transfer tape through the spool core of a feed spool arranged laterally of and radially offset from the take-up spool in the housing of a transfer dispenser or in a refill cassette for a transfer dispenser, comprising a first gearwheel which is driven by the feed spool and which meshes with a second gearwheel designed to drive the take-up spool, the pitch diameter of the second gearwheel being smaller than that of the first gearwheel, a slipping clutch being provided between the spool core of one of the two spools and the associated gearwheel and a radially projecting annular disc being disposed on each spool core and its side facing the other spool.
Transfer dispensers are widely used in offices and homes. They are hand-held devices for transferring a film, for example an adhesive film or a cover-up film, from a carrier tape to a substrate, the film-coated carrier tape being wound onto a feed spool in the dispenser housing and being guided from the feed spool to an applicator foot projecting from the housing. By means of the applicator foot, the film-coated carrier tape can be pressed onto a substrate, the film layer being separated from the carrier tape and transferred to the substrate in conjunction with the reversal of the tape at the applicator foot. The empty carrier tape is then reversed at the applicator foot and returned to a take-up spool in the dispenser housing. The feed spool and the take-up spool and also the applicator foot are often accommodated together in a cassette.
The feed spool is made to rotate by the removal of the carrier tape from the feed spool when the dispenser is in use, i.e. during its movement over the substrate. The feed spool drives the take-up spool through a suitable intermediate gear and the slipping clutch, the design of the gear having to take into account the fact that the carrier tape must always be kept under a certain tension irrespective of the offwinding diameter of the carrier tape on the feed spool and the winding-on diameter of the carrier tape on the take-up spool.
In known transfer dispensers, the take-up spool and the feed spool can be arranged in tandem in the same plane although this does lead to relatively large dispensers. Instead of this, however, the two spools may also be arranged beside one another, both coaxial and axially slightly offset spool arrangements being known. In this way, the dispenser housing can be made considerably shorter in its longitudinal direction than in the case of spools arranged in tandem in one plane, the housing having to be made slightly thicker solely in the vicinity of the spool mounting as a result of the juxtaposition of the spools. This particular solution is adopted above all when the dispenser housing is intended to be in the form of an "elongate" housing where part of the housing is relatively small in cross-section and elongated, for example in the form of an elongate cylinder or the like, which enables the housing to be held there like a relatively thick pencil or fountain pen. The larger and slightly thicker part of the housing is arranged at the end of this elongate part to accommodate the two spools, being situated above the back of the user's hand when the dispenser is in use (similarly to the cap of a fountain pen during writing), i.e. in a position where there is no interference with the convenient holding of the dispenser in the hand of the user at the elongate, thinner part of the housing.
A particular concern in the design of these "elongate" transfer dispensers is also to configure the larger part of the housing at the end of the elongate dispenser in such a way that its width (i.e. the space it occupies axially of the spools) is as small as possible so that the dispenser as a whole is small and handy.
In one known transfer dispenser of the type mentioned at the beginning marketed under the name of "Tombo" where the two spools are arranged in a refill cassette, the refill cassette has a longitudinally extending intermediate wall section on one side of which the feed spool and on the other side of which the take-up spool are mounted for rotation. The spool core of the feed spool is disposed on a rotary mounting which in turn is mounted for rotation on a spindle integral with the cassette and projecting from the intermediate wall section thereof. The spool core of the feed spool is held on the rotary mounting by friction so that a slipping clutch operating by friction is formed between the two. The rotary mounting in turn is provided with a radially projecting annular disc which projects radially at the axial end of the spool core of the feed spool that faces the intermediate wall section of the cassette so that the tape is prevented from slipping sideways off its roll towards the intermediate wall section when the transfer dispenser is in use. Formed integrally with the rotary mounting between the annular disc and the intermediate wall section is a gearwheel which meshes with a second smaller gearwheel of which the central axis is offset from the central axis of the rotary mounting longitudinally of the transfer dispenser and which, in turn, comprises an integral lateral shaft section through which it is rotatably mounted in the intermediate wall section of the cassette. This lateral shaft section projects through the intermediate wall of the cassette to the other side thereof where the spool core of the take-up spool is mounted for rotation thereon.
In addition, radially projecting side discs are fitted from outside onto the central spindles of the feed and take-up spools at their free axial ends to prevent the carrier tape from slipping sideways off its roll on this side, too, when the transfer dispenser is in use.
In view of the gear arrangement of the refill cassette of this known transfer dispenser, the space occupied transversely of the cassette, i.e. axially of the spools, is comparatively large because not only do the spool widths have to be accommodated here, allowance also has to be made for the width of the outer cover discs on both spools, the thickness of the two annular discs, the thickness of the intermediate wall section and the thickness of the two gearwheels on the side of the feed spool. In addition, a comparatively large number of parts is involved in the construction of the described gear arrangement of this known transfer dispenser.